At present, for an electronic cigarette which can be repeatedly used, after liquid solution is used up, new liquid solution can be injected into a cartridge of the electronic cigarette, thus, the electronic cigarette can be continuously used. However, a suction nozzle of the electronic cigarette needs to be removed for injecting the liquid solution into the cartridge, which is troublesome. In addition, the suction nozzle removed from the electronic cigarette may easily drop off to get dirty or get lost, which is inconvenient.